The present invention relates to a method and a program for measuring binocular visual performance, and design and manufacturing methods for designing and manufacturing eyeglass lenses using the measurement result.
One of eyesight test items, a binocular visual performance test is known. The binocular visual performance test includes a simultaneous perception test, a fusion test and a stereoscopic viewing test. Eyesight tests of this type are described in Japanese Patent Provisional Publications No. 2010-99335A (hereafter, referred to as patent document #1) and No. 2010-75755A (hereafter, referred to as patent document #2).
The stereoscopic viewing test described in patent document #1 is performed using a HMD (Head Mounted Display). Specifically, a subject views an object as a virtual image wearing the HMD on one eye, and simultaneously views the object with the other eye as naked vision. The subject perceives retinal images of the object as a three dimensional object when the object viewed as the virtual image and the object viewed with the naked eye are in Panum's fusional area although the retinal images are not at corresponding points. In the test, the virtual image is moved from a state where the subject is able to perform stereoscopic viewing, so as to change binocular parallax. As the binocular parallax changes, the left and right retinal images deviate from the Panum's fusional area at a certain point in time. At this time, the subject perceives a double image of the object. As described above, the stereoscopic viewing test in patent document #1 performs a test of the stereoscopic viewing by measuring a breaking point which allows the subject to achieve the fusion for the object.
In an ophthalmologic testing method described in patent document #2, the binocular visual performance is tested using an indicator projected on a shallow hemisphere screen of an ophthalmologic testing apparatus. For example, in the fusion test, an image for a left eye and an image for a right eye are projected to overlap with each other so that the images can be recognized as a single image. Then, the two projected images are moved to depart from each other. In the ophthalmologic testing method described in patent document #2, a breaking point at which the shifted two images are recognized as a double image is measured to perform the fusion test.